Three-dimension butler matrix

ABSTRACT

The disclosure provides a Butler Matrix. The Butler Matrix includes: a plurality of couplers having a circuit of a cuboid structure, a plurality of crossover lines, a plurality of three-dimensional crossover lines having a three-dimensional structure, and a plurality of phase shifters. The phase shifters, the crossover lines, and the three-dimension crossover lines are been coupled between one of the couplers and the other of the couplers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 106116050, filed on May 16, 2017. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

TECHNICAL FIELD

The disclosure relates to a three-dimensional Butler Matrix.

BACKGROUND

Despite the development of science and technology, further efforts arestill required in the wireless communication technologies relating tomillimeter wave (mmWave). In general, the first challenge is that thewave energy may be significantly attenuated during transmission of themmWave. The attenuation is closely related to the high frequency band atwhich a mmWave communication system operates and a rather largebandwidth required for communication in the mmWave communication system.More specifically, compared with the third generation (3G) or the fourthgeneration (4G) communication system commonly used nowadays, the mmWavecommunication system adopts a relatively higher frequency band forcommunication. It is known that an intensity of an electromagnetic waveenergy received by a receiver is negatively proportional to a square ofa signal transmission distance and is positively proportional to awavelength of an electromagnetic signal. Therefore, the degree to whichthe signal energy of the mmWave communication system attenuates issignificantly increased because of the high frequency signal with ashorter wavelength adopted in the mmWave communication system. Inaddition, the use of the high frequency signal also results in a drasticdecrease in antenna aperture, and may also result in a decrease in thesignal energy for signal transmission in the mmWave communicationsystem. Therefore, to ensure the communication quality, a transceiver inthe mmWave communication system normally requires a multi-antennabeamforming technology to reduce signal energy attenuation and thusfacilitate the performance of signal transmission and reception.

Generally speaking, the multi-antenna beamforming technology includesarranging an antenna array including a plurality of antennas in a basestation/user apparatus and controlling the antennas so that the basestation/user apparatus may generate a directional beam. The beamformingtechnology achieved with the antenna array is crucial to the performanceof the mmWave communication system. It is common to adopt a ButlerMatrix to control beamformed signals of an antenna array. However, theButler Matrix is only able to control the directionality of beams in atwo-dimensional space, such as controlling a horizontal direction of thebeamformed signals. However, a Butler Matrix only capable of controllingthe horizontal direction is insufficient for a case where a transmittingend has a difference in height, for example.

SUMMARY

The disclosure provides a Butler Matrix. The Butler Matrix includes: aplurality of couplers having a circuit of a cuboid structure, aplurality of crossover lines, a plurality of three-dimensional crossoverlines having a three-dimensional structure, and a plurality of phaseshifters. The crossover lines, the three-dimensional crossover lines,and the phase shifters are coupled between one of the couplers andanother of the couplers.

Several exemplary embodiments accompanied with figures are described indetail below to further describe the disclosure in details.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide further understanding,and are incorporated in and constitute a part of this specification. Thedrawings illustrate exemplary embodiments and, together with thedescription, serve to explain the principles of the disclosure.

FIG. 1A is a schematic view illustrating a Butler Matrix.

FIG. 1B is a schematic view illustrating combining two-dimensionalButler Matrices controlling horizontal and vertical directions of abeam.

FIG. 2A is a schematic view illustrating a three-dimensional coupleraccording to an embodiment of the disclosure.

FIG. 2B is a schematic view illustrating a three-dimensional crossoverline according to an embodiment of the disclosure.

FIG. 3A is a schematic view illustrating a three-dimensional ButlerMatrix according to an embodiment of the disclosure.

FIG. 3B is a schematic view illustrating the three-dimensional ButlerMatrix in the embodiment shown in FIG. 3A in greater detail.

FIG. 3C is a schematic view illustrating a three-dimensional crossoverline of the three-dimensional Butler Matrix of FIG. 3A.

FIG. 3D is a schematic view illustrating an embodiment of anotherthree-dimensional crossover line of the three-dimensional Butler Matrixshown in FIG. 3A.

FIG. 4 is a schematic cross-sectional view illustrating a multi-layercircuit board implementing a three-dimensional Butler Matrix accordingto an embodiment of the disclosure.

FIG. 5A is a circuit diagram illustrating a three-dimensional ButlerMatrix according to an embodiment of the disclosure.

FIGS. 5B and 5C are layout diagrams of the multi-layer circuit boardcorresponding to the circuit diagram of FIG. 5A.

FIG. 6A is a circuit diagram illustrating a three-dimensional ButlerMatrix according to an embodiment of the disclosure.

FIG. 6B is a layout diagram of the multi-layer circuit boardcorresponding to the circuit diagram of FIG. 6A.

FIG. 7A is a circuit diagram illustrating a three-dimensional ButlerMatrix according to an embodiment of the disclosure.

FIG. 7B is a layout diagram of the multi-layer circuit boardcorresponding to the circuit diagram of FIG. 7A.

FIGS. 8A, 8B, 8C, and 8D are layout diagrams of a multi-layer circuitboard according to an embodiment of the disclosure.

FIGS. 9A and 9B are schematic view illustrating a simulated channelperformance of beamformed signals controlled by a three-dimensionalButler Matrix according to an embodiment of the disclosure.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

Based on the above, in addition to simultaneously controlling thehorizontal direction and the vertical direction of the beam, the ButlerMatrix of the disclosure can be manufactured with only a manufacturingprocess of a single multi-layer circuit board. Thus, the size and themanufacturing cost of the Butler Matrix are able to be reducedsignificantly.

FIG. 1A is a schematic view illustrating a Butler Matrix 100. A way forcontrolling beamformed signals of an antenna array with a Butler Matrixis common in the related field. The Butler Matrix 100 of FIG. 1A hasfour input ends and four output ends, and the Butler Matrix 100 includesa plurality of couplers 101, a plurality of phase shifters 103, and aplurality of crossover lines 105. Input ends i1, i2, i3, and i4 arerespectively coupled to a plurality of output ends o1, o2, p3, and o4.When a signal is input from different input ends, the signal maygenerate different phase differences at different output ends. Takingthe input ends i1 and i2 as an example, since the phase differencesbetween the input ends i1 and i2 and the output ends o1, o2, o3, and o4are respectively different, beamformed signals having different phasedifferences and directional properties may be generated when a signal isinput from the input end i1 or from the input end i2.

The Butler Matrix shown in FIG. 1A is only able to adjust a beamformedsignal in a horizontal direction. However, when a receiving end of thebeamformed signal has a height difference, the Butler Matrix onlycapable of controlling the horizontal direction is insufficient tohandle such case. Therefore, a Butler Matrix capable of controlling ahorizontal direction as well as a vertical direction of a beam isrequired.

FIG. 1B is a schematic view illustrating combining two-dimensionalButler Matrices controlling the horizontal and vertical directions of abeam. The Butler Matrix of FIG. 1B is formed by a plurality of theButler Matrices 100. A left half 110 of FIG. 1B is formed by stackingfour Butler Matrices 100 arranged horizontally, and a right half 130 ofFIG. 1B is formed by stacking four Butler Matrices 100 arrangedvertically. The Butler Matrices of FIG. 1B are capable of controlling abeam two-dimensionally. For example, a signal input from an input end 1and a signal input from an input end 2 may render two beams in differenthorizontal directions, and a signal input from the input end 1 and asignal input from an input end 5 may render two beams in differentvertical directions. While the Butler Matrices of FIG. 1B are able ofcontrolling a beam two-dimensionally, the configuration shown in FIG. 1Brequires a set of Butler Matrices stacked horizontally and a set ofButler Matrices stacked vertically. Therefore, the configuration has alarger size as well as a higher manufacturing cost.

FIG. 2A is a schematic view illustrating a three-dimensional coupler 200according to an embodiment of the disclosure. The three-dimensionalcoupler 200 has a circuit of a cuboid structure, and thethree-dimensional coupler 200 may include a first input end I1, a secondinput end I2, a third input end I3, and a fourth input end I4 forming afirst surface S1 of the cuboid structure. In addition, thethree-dimensional coupler 200 may also include a first output end O1, asecond output end O2, a third output end O3, and a fourth output end O4forming a second surface S2 of the cuboid structure. The first surfaceS1 and the second surface S2 do not intersect with each other. An m^(th)input end and an m^(th) output end of the three-dimensional coupler 200form a side of the cuboid structure, wherein m is a positive integerless than or equal to 4. Specifically, the first input end I1 and thefirst output end O1, the second input end I2 and the second output endO2, the third input end I3 and the third output end O3, and the fourthinput end I4 and the fourth output end O4 respectively form a side 201,a side 203, a side 205, and a side 207 of the cuboid structure. In anembodiment, in the cuboid structure of the three-dimensional coupler200, each surface except for the first surface S1 and the second surfaceS2 may be implemented to be a two-dimensional quadrature hybrid coupler,for example. However, it should be noted that the disclosure is notlimited thereto.

The respective input ends of the three-dimensional coupler 200 areinsulated from each other, and the respective output ends are alsoinsulated from each other. Therefore, for the input ends, sides 209,211, 213, and 215 of the cuboid structure may be considered as beingformed as insulators, and for the output ends, sides 217, 219, 221, and223 may be considered as being formed as insulators.

In the cuboid structure of the three-dimensional coupler 200, there is aphase difference θ between an input end and an output end on a diagonalof the same surface of the cuboid structure. Taking a third surface S3as an example, the surface S3 is formed by the input ends I1 and I2 andthe output ends O1 and O2. In addition, the input end I1 and the outputend O2 are on a diagonal d1 of the surface S3. Thus, there is the phasedifference θ between the input end I1 and the output end O2. Similarly,since the input end I2 and the output end O1 are on a diagonal d2 of thesurface S3, there is also the phase difference θ between the input endI2 and the output end O1. Comparatively, since the input end I1 and theoutput end O1 are not on a diagonal of the surface S3, there is no phasedifference between the input end I1 and the output end O1. Taking afourth surface S4 as another example, on the surface S4, there is thephase difference θ between the input end I2 and the output end O4, andthere is also the phase difference θ between the input end I4 and theoutput end O2. In an embodiment, the phase difference θ may be 90degrees. However, the disclosure is not limited thereto.

FIG. 2B is a schematic view illustrating a three-dimensional crossoverline 250 according to an embodiment of the disclosure. Thethree-dimensional crossover line 250 is formed by two horizontallyarranged crossover lines 251 and two vertically arranged crossover lines253. An input end A of the three-dimensional crossover line 250 iscoupled to an output end A′, an input end B is coupled to an output endB′, an input end C is coupled to an output end C′, and an input end D iscoupled to the output end D′.

FIG. 3A is a schematic view illustrating a three-dimensional ButlerMatrix 300 according to an embodiment of the disclosure. The ButlerMatrix 300 may be formed by a first coupler set 350 and a second couplerset 370. The first coupler set 350 at least has four three-dimensionalcouplers 200, respectively corresponding to a three-dimensional couplerC1, a three-dimensional coupler C2, a three-dimensional coupler C3, anda three-dimensional coupler C4 shown in FIG. 3B. The second coupler set370 at least has four three-dimensional couplers 200, respectivelycorresponding to a three-dimensional coupler C1′, a three-dimensionalcoupler C2′, a three-dimensional coupler C3′, and a three-dimensionalcoupler C4′ shown in FIG. 3B.

The first surfaces S1 of the respective couplers 200 in the firstcoupler set 350 may form an input array, and respective sides of theinput array have the same number of input ends. In the embodiment, thefirst surfaces S1 of the three-dimensional coupler C1, thethree-dimensional coupler C2, the three-dimensional coupler C3, and thethree-dimensional coupler C4 form a four-by-four input array 310 having16 input ends respectively represented as input ends PI1 to PI16. Forexample, the four input ends I1, I2, I3, and I4 of the three-dimensionalcoupler C1 may respectively form the input ends PI1, PI2, PI5 and PI6 ofthe four-by-four input array 310.

The second surfaces S2 of the respective couplers 200 in the secondcoupler set 370 may form an output array, and respective sides of theoutput array have the same number of output ends. In the embodiment, thesecond surfaces S2 of the three-dimensional coupler C1′, thethree-dimensional coupler C2′, the three-dimensional coupler C3′, andthe three-dimensional coupler C4′ form a four-by-four output array 330having 16 output ends respectively represented as output ends PO1 toPO16. For example, the four output ends O1, O2, O3, and O4 of thethree-dimensional coupler C may respectively form the output ends PO1,PO2, PO5 and PO6 of the four-by-four output array 330.

When the three-dimensional Butler Matrix 300 is used, at least one inputend of at least one of the three-dimensional couplers 200 of the firstcoupler set 350 is coupled to the respective output ends of therespective three-dimensional couplers 200 of the second coupler set 370,so as to output beamformed signals corresponding to the input end fromthe respective output ends. For example, assuming that an input signal sis input into the three-dimensional Butler Matrix 300 through the inputend PI1, the input signal s may be transmitted to the respective outputends PO1 to PO16 via a plurality of different paths. Therefore, aplurality of output signals corresponding to the respective output endsPO1 to PO16 may be turned into the input signals s having differentphase differences, and beamformed signals formed by the output signalsof the respective output ends PO1 to PO16 are thus directional due tothe phase differences of different output signals.

In the input array 310, the beamformed signals corresponding to theinput ends on the same row have phase differences in differenthorizontal directions. For example, an output beam obtained by inputtingthe signal s from the input end PI1 has a different horizontal directionthan the horizontal direction of an output beam obtained by inputtingthe signal s from the input end PI2. In addition, the correspondingbeamformed signals of the input ends on the same column have phasedifferences in different vertical directions. For example, an outputbeam obtained by inputting the signal s from the input end PI1 has adifferent vertical direction than the vertical direction of an outputbeam obtained by inputting the signal s from the input end PI5.

FIG. 3B is a schematic view illustrating the three-dimensional ButlerMatrix 300 in the embodiment shown in FIG. 3A in greater detail. In thethree-dimensional Butler Matrix 300, a j^(th) output end of an i^(th)coupler in the first coupler set 350 is coupled to an i^(th) input endof a j^(th) coupler of the second coupler set 370, wherein i and j arepositive integers, j is less than or equal to 4, i is less than or equalto N, and N is a positive integer that is a power of 4 or more.

Specifically, a first output end c1O1, a second output end c1O2, a thirdoutput end c1O3, and a fourth output end c1O4 of a three-dimensionalcoupler c1 of the first coupler set 350 are respectively andsequentially coupled to a first input end c1′I1 of a three-dimensionalcoupler c1′, a first input end c2′I1 of a three-dimensional coupler c2′,a first input end c3′I1 of a three-dimensional coupler c3′, and a firstinput end c4′I1 of a three-dimensional coupler c4′ of the second couplerset 370.

A first output end c2O1, a second output end c2O2, a third output endc2O3, and a fourth output end c2O4 of a three-dimensional coupler c2 ofthe first coupler set 350 are respectively and sequentially coupled to asecond input end c1′I2 of the three-dimensional coupler c1′, a secondinput end c2′I2 of the three-dimensional coupler c2′, a second input endc3′I2 of the three-dimensional coupler c3′, and a second input end c4′I2of the three-dimensional coupler c4′ of the second coupler set 370.

A first output end c3O1, a second output end c3O2, a third output endc3O3, and a fourth output end c3O4 of a three-dimensional coupler c3 ofthe first coupler set 350 are respectively and sequentially coupled to athird input end c1′I3 of the three-dimensional coupler c1′, a thirdinput end c2′I3 of the three-dimensional coupler c2′, a third input endc3′I3 of the three-dimensional coupler c3′, and a third input end c4′I3of the three-dimensional coupler c4′ of the second coupler set 370.

A first output end c4O1, a second output end c4O2, a third output endc4O3, and a fourth output end c4O4 of a three-dimensional coupler c4 ofthe first coupler set 350 are respectively and sequentially coupled to afourth input end c1′I4 of the three-dimensional coupler c1′, a fourthinput end c2′I4 of the three-dimensional coupler c2′, a fourth input endc3′I4 of the three-dimensional coupler c3′, and a fourth input end c4′I4of the three-dimensional coupler c4′ of the second coupler set 370.

In the embodiment, the numbers of the couplers 200 of the first couplerset 350 and the second coupler set 370 in the three-dimensional ButlerMatrix 300 are both 4. In other words, the three-dimensional ButlerMatrix 300 has 16 inputs and 16 outputs. Still, people having ordinaryskills in the art shall appreciate that the framework of the disclosuremay also be implemented in a three-dimensional Butler Matrix whosenumbers of inputs and outputs are greater than 16 based on thethree-dimensional Butler Matrix 300 of the disclosure. For example, thenumbers N of the couplers 200 in the first coupler set 350 and thesecond coupler set 370 in the three-dimensional Butler Matrix 300 mayalso be positive integers that are a power of 4 or more.

In an embodiment of the three-dimensional Butler Matrix 300, whichincludes a plurality of couplers having a circuit of a cuboid structure,a plurality of crossover lines, a plurality of three-dimensionalcrossover lines having a three-dimensional structure, and a plurality ofphase shifters. The crossover lines, the three-dimensional crossoverlines, and the phase shifters are coupled between one of the couplersand another of the couplers. The connections between the respectiveterminals in the respective three-dimensional couplers are described inTable 1. Table 1 lists combinations of electrically connected terminalsbetween the respective three-dimensional couplers 200.

TABLE 1 Terminal 1 Terminal 2 C1O1 C1′I1 C1O2 C2′I1 C1O3 C3′I1 C1O4C4′I1 C2O1 C1′I2 C2O2 C2′I2 C2O3 C3′I2 C2O4 C4′I2 C3O1 C1′I3 C3O2 C2′I3C3O3 C3′I3 C3O4 C4′I3 C4O1 C1′I4 C4O2 C2′I4 C4O3 C3′I4 C4O4 C4′I4

One of a combination of a first phase shifter 301 and a second phaseshifter 303, a combination of at least one of the plurality of crossoverlines 305 and the second phase shifter 303, a combination of the firstphase shifter 301 and at least one of the plurality of crossover lines305, and at least one of the plurality of three-dimensional crossoverlines 250 is coupled between the j^(th) output end of the i^(th)three-dimensional coupler 200 of the first coupler set 350 and thei^(th) input end of the j^(th) coupler of the second coupler set 370 ofthe three-dimensional Butler Matrix 300, wherein i and j are positiveintegers less than or equal to 4.

Specifically, the first phase shifters 301 are coupled to the firstoutput ends c1O1 and c3O1 and the third output ends c1O3 and c3O3 of thefirst coupler c1 and the third coupler c3 of the first coupler set 350.In addition, the phase shifters 301 are also coupled to the secondoutput ends c2O2 and c4O2 and the fourth output ends c2O4 and c4O4 ofthe second coupler c2 and the fourth coupler c4 of the first coupler set350.

Besides, the second phase shifters 303 are coupled to the first inputends c1′I1 and c2′I1 and the second input ends c1′I2 and c2′I2 of thefirst coupler c1′ and the second coupler c2′ of the second coupler set370. In addition, the second phase shifters 303 are also coupled to thethird input ends c3′I3 and c413 and the fourth input ends c3′I4 andc4′I4 of the third coupler c3′ and the fourth coupler c4′ of the secondcoupler set 370.

In the embodiment, the first phase shifter 301 serves to control thehorizontal direction of the beamformed signal, and the second phaseshifter 303 serves to control the vertical direction of the beamformedsignal. In the embodiment, the first phase shifter 301 and the secondphase shifter 303 respectively have a phase difference of 45 degrees.However, the disclosure is not limited thereto. Locations of the firstphase shifters 301 and the second shifters 303 are also interchangeable.For example, the second phase shifters 303 may be arranged at thelocations where the first phase shifters 301 are originally located inthe three-dimensional Butler Matrix 300, and the first phase shifters301 may be arranged at the locations where the second phase shifters 303are originally located in the three-dimensional Butler Matrix 300. Thedisclosure is not limited thereto.

Four crossover lines 305 are coupled between the first coupler set 350and the second coupler set 370 of the three-dimensional Butler Matrix300. The crossover lines 305 allow the output ends and the input ends ofthe respective three-dimensional couplers 200 to be coupled to eachother. Table 2 lists combinations of terminals coupled to each otherthrough the crossover lines 305.

TABLE 2 Terminals of three-dimensional couplers First set of crossoverline c1O2 c2′I1 305 c2O1 c1′I2 Second set of crossover c2O4 c4′I2 line305 c4O2 c2′I4 Third set of crossover line c3O4 c4′I3 305 c4O3 c3′I4Fourth set of crossover line c1O3 c3′I1 305 c3O1 c1′I3

FIG. 3C is a schematic view illustrating the three-dimensional crossoverline 250 of the three-dimensional Butler Matrix 300 of FIG. 3A. In theembodiment, the third three-dimensional crossover line 250 is furthercoupled between the first coupler set 350 and the second coupler set 370of the three-dimensional Butler Matrix 300. Details concerningconnections of the three-dimensional crossover line 250 are shown inFIG. 3C. In the three-dimensional crossover line 250 shown in FIG. 3C, ak^(th) input end and a k^(th) output end are electrically connected witheach other, and are respectively connected to a (5−k)^(th) output end ofa k^(th) coupler in the first coupler set 350 and a k^(th) input end ofa (5−k)^(th) coupler of the second coupler set 370, wherein k is apositive integer and less than or equal to 4.

Specifically, a first input end A and a first output end A′ of thethree-dimensional crossover line 250 are electrically connected witheach other, and are respectively coupled to the fourth output end c1O4of the first coupler c1 in the first coupler set 350 and the first inputend c4′I1 of the fourth coupler c4′ in the second coupler set 370.

A second input end B and a second output end B′ of the three-dimensionalcrossover line 250 are electrically connected with each other, and arerespectively coupled to the third output end c2O3 of the second couplerc2 in the first coupler set 350 and the second input end c3′I2 of thethird coupler c3′ in the second coupler set 370.

A third input end C and a third output end C′ of the three-dimensionalcrossover line 250 are electrically connected with each other, and arerespectively coupled to the second output end c3O2 of the third couplerc3 in the first coupler set 350 and the third input end c2′I3 of thesecond coupler c2′ in the second coupler set 370.

A fourth input end D and a fourth output end D′ of the three-dimensionalcrossover line 250 are electrically connected with each other, and arerespectively coupled to the first output end c4O1 of the fourth couplerc4 in the first coupler set 350 and the fourth input end c1′I4 of thefirst coupler c1′ in the second coupler set 370.

Four crossover lines 305 are coupled between the second coupler set 370and the output array 330 of the three-dimensional Butler Matrix 300. Thecrossover lines 305 allow the output ends of the respectivethree-dimensional couplers 200 to be coupled with the output array 330.Table 3 lists combinations of terminals coupled to each other throughthe crossover lines 305.

TABLE 3 Output ends Terminals of of the output three-dimensionalcouplers array First set of crossover line c1′O2 PO3 305 c2′O1 PO2Second set of crossover c2′O4 PO12 line 305 c4′O2 PO8 Third set ofcrossover line c3′O4 PO15 305 c4′O3 PO14 Fourth set of crossover linec1′O3 PO9 305 c3′O1 PO5

FIG. 3D is a schematic view illustrating an embodiment of anotherthree-dimensional crossover line 250 of the three-dimensional ButlerMatrix 300 shown in FIG. 3A. In the embodiment, the thirdthree-dimensional crossover line 250 is also coupled between the secondcoupler set 370 and the output array 330 of the three-dimensional ButlerMatrix 300. Details concerning connection of the three-dimensionalcrossover line 250 are shown in FIG. 3D.

Specifically, the first input end A and the first output end A′ of thethree-dimensional crossover line 250 are electrically connected witheach other, and are respectively coupled to the fourth output end c1′O4of the first coupler c1′ in the second coupler set 370 and the outputend PO11 of the output array 330.

The second input end B and the second output end B′ of thethree-dimensional crossover line 250 are electrically connected witheach other, and are respectively coupled to the third output end c2′O3of the second coupler c2′ in the second coupler set 370 and the outputend PO10 of the output array 330.

The third input end C and the third output end C′ of thethree-dimensional crossover line 250 are electrically connected witheach other, and are respectively coupled to the second output end c3′O2of the third coupler c3′ in the second coupler set 370 and the outputend PO07 of the output array 330.

The fourth input end D and the fourth output end D′ of thethree-dimensional crossover line 250 are electrically connected witheach other, and are respectively coupled to the first output end c4′O1of the fourth coupler c4′ in the second coupler set 370 and the outputend PO06 of the output array 330.

Referring back to FIG. 2A, on the surface S3 and a surface S5 (thesurface S5 is formed by I3, I4, O3, and O4) of each of thethree-dimensional couplers 200 of the three-dimensional Butler Matrix300, the phase difference θ between one of the input ends and one of theoutput ends on the diagonal of the third surface and the fifth surfacecorrespondingly is in relation to horizontal control on the beamformedsignal. On the surface S4 and a surface S6 (the surface S6 is formed byI1, I3, O1, and O3) of each of the three-dimensional couplers 200, thephase difference θ between one of the input ends and one of the outputends on the diagonal of the fourth surface and the sixth surfacecorrespondingly is in relation to vertical control on the beamformedsignal.

FIG. 4 is a schematic cross-sectional view illustrating a multi-layercircuit board 400 implementing the three-dimensional Butler Matrix 300according to an embodiment of the disclosure. The three-dimensionalButler Matrix 300 of the disclosure may be carried out by a singlemulti-layer circuit board 400, as shown in FIG. 4. The multi-layercircuit board 400 may be a circuit board with 11 layers. In addition,circuit layers L0 and L10 are respectively the output array 330 and theinput array 310 of the three-dimensional Butler Matrix 300. Circuitlayers L1, L3, L5, L7, and L9 are respectively grounding layers. Signalsare transmitted between the respective circuit layers through vias.

FIG. 5A is a circuit diagram illustrating the three-dimensional ButlerMatrix 300 according to an embodiment of the disclosure. FIGS. 5B and 5Care layout diagrams of the multi-layer circuit board 400 correspondingto the circuit diagram of FIG. 5A. In addition, FIG. 5B is a layoutdiagram of a circuit layer L2, and FIG. 5C is a layout diagram of acircuit layer L4. The circuit layers L2 and L4 mainly include thethree-dimensional crossover line 250 with connections shown in FIG. 3D,the crossover line 305 shown in FIG. 5A, and other wires 501 in thecircuit board.

FIG. 6A is a circuit diagram illustrating the three-dimensional ButlerMatrix 300 according to an embodiment of the disclosure. FIG. 6B is alayout diagram of the multi-layer circuit board 400 corresponding to thecircuit diagram of FIG. 6A. In addition, FIG. 6B is a layout diagram ofthe circuit layer L6. The circuit layer L6 mainly includes thethree-dimensional crossover line 250 with the connections shown in FIG.3C, the crossover line 305 shown in FIG. 6A, all the second phaseshifters 303, the four three-dimensional couplers c1′, c2′, c3′, and c4′in the second coupler set 370, and a quadrature coupler 601 relating tothe horizontal control on the beamformed signal and a quadrature coupler603 relating to the vertical control on the beamformed signal.

FIG. 7A is a circuit diagram illustrating the three-dimensional ButlerMatrix 300 according to an embodiment of the disclosure. FIG. 7B is alayout diagram of the multi-layer circuit board 400 corresponding to thecircuit diagram of FIG. 7A. In addition, FIG. 7B is a layout diagram ofa circuit layer L8. The circuit layer L8 mainly includes thethree-dimensional crossover line 250 with the connections shown in FIG.3C, the crossover line 305 shown in FIG. 7A, all the first phaseshifters 301, the four three-dimensional couplers c1, c2, c3, and c4 inthe first coupler set 350, the quadrature coupler 601 relating to thehorizontal control on the beamformed signal and the quadrature coupler603 relating to the vertical control on the beamformed signal, and otherwires 501 in the circuit board.

FIGS. 8A, 8B, 8C, and 8D are layout diagrams of the multi-layer circuitboard 400 according to an embodiment of the disclosure. FIGS. 8A, 8B,8C, and 8D illustrate signal transmission paths between the respectivelayers of the multi-layer circuit board 400 in greater detail. FIG. 8Aillustrates a layout diagram of the circuit layer L2, and shows signaltransmission paths between the circuit layers L2 and L4 and between thecircuit layers L2 and L0. FIG. 8B illustrates a layout diagram of thecircuit layer L4, and shows signal transmission paths between thecircuit layers L4 and L2 and between the circuit layers L4 and L6. FIG.8C illustrates a layout diagram of the circuit layer L6, and showssignal transmission paths between the circuit layers L6 and L4 andbetween the circuit layers L6 and L8. FIG. 8D illustrates a layoutdiagram of the circuit layer L8, and shows signal transmission pathsbetween the circuit layers L8 and L6 and between the circuit layers L8and L10.

FIGS. 9A and 9B are schematic view illustrating a simulated channelperformance of beamformed signals controlled by the three-dimensionalButler Matrix 300 according to an embodiment of the disclosure.Referring to FIGS. 9A and 9B, FIG. 9B shows channel performances of fourbeamformed signals generated by the three-dimensional Butler Matrix 300.Specifically, curves m1, m2, m3, and m4 in FIG. 9B respectivelycorrespond to channel performances of beamformed signals generated fromthe input signals input from the input ends PI6, PI8, PI5, and PI7 ofthe input array 310. Since the input ends PI6, PI8, PI5, and PI7 are onthe same row of the input array 310, vertical phase differences betweenthe signals input from the input ends PI6, PI8, PI5, and PI7 and signalsof any output end of each output array 330 are completely the same.Therefore, the beamformed signals represented by the curves m1, m2, m3,and m4 have the same emission angle in the vertical direction.

Taking the output ends PO1, PO2, PO3, and PO4 as an example, when asignal is input to the input end PI1, there is a horizontal phasedifference of −45 degrees, for example, between the signals output fromthe output ends PO1, PO2, PO3, and PO4. However, there is no verticalphase difference between the signals output from the output ends PO1,PO2, PO3, and PO4. Similarly, when the signal is input to the input endPI2, there is a horizontal phase difference of +135 degrees, forexample, between the signals output from the output ends PO1, PO2, PO3,and PO4. However, there is no vertical phase difference between thesignals output from the output ends PO1, PO2, PO3, and PO4. Taking theoutput ends PO1, PO5, PO9, and PO13 as another example, when a signal isinput to the input end PI1, there is a vertical phase difference of +45degrees, for example, between the signals output from the output endsPO1, PO5, PO9, and PO13. However, there is no horizontal phasedifference between the signals output from the output ends PO1, PO5,PO9, and PO13. Similarly, when there is a vertical phase difference of45 degrees between the signals output by the output ends PO1, PO5, PO9,and PO13, when the signal is input to the input end PI5, there is avertical phase difference of −135 degrees, for example, between thesignals output from the output ends PO1, PO5, PO9, and PO13. However,there is no horizontal phase difference between the signals output fromthe output ends PO1, PO5, PO9, and PO13. Accordingly, when a signal isinput from the input end PI1, the phase difference between therespective horizontally arranged output ends is different from the phasedifference between the respective horizontally arranged output ends whenthe signal is input from the input end PI2. Besides, when inputting asignal from the input end PI1, the phase difference between therespective vertically arranged output ends is the same as the signalinputted from the input end PI2. Therefore, a beamformed signal obtainedby inputting a signal from the input end PI6 and a beamformed signalobtained by inputting a signal from the input end PI8 have the samevertical angle but different horizontal angles, as shown in PI6 and PI8of FIG. 9A.

In view of the foregoing, in addition to simultaneously controlling thehorizontal direction and the vertical direction of the beam, the ButlerMatrix of the disclosure can be manufactured with only a manufacturingprocess of a multi-layer circuit board. Therefore, the size and themanufacturing cost of the Butler Matrix are able to be reducedsignificantly.

It will be clear to those skilled in the art that various modificationsand variations can be made to the structure of the disclosed embodimentswithout departing from the scope or spirit of the disclosure. In view ofthe foregoing, it is intended that the disclosure cover modificationsand variations of this disclosure provided they fall within the scope ofthe following claims and their equivalents.

What is claimed is:
 1. A Butler Matrix, comprising: a plurality ofcouplers, wherein each of the couplers has a circuit of a cuboidstructure; a plurality of crossover lines; a plurality ofthree-dimensional crossover lines, wherein each of the three-dimensionalcrossover lines has a three-dimensional structure; and a plurality ofphase shifters, wherein the crossover lines, the three-dimensionalcrossover lines, and the phase shifters are coupled between one of thecouplers and another one of the couplers.
 2. The Butler Matrix asclaimed in claim 1, wherein each of the couplers comprises: a pluralityof input ends, comprising a first input end, a second input end, a thirdinput end, and a fourth input end forming a first surface of the cuboidstructure; and a plurality of output ends, comprising a first outputend, a second output end, a third output end, and a fourth output endforming a second surface of the cuboid structure, wherein the firstsurface and the second surface of the cuboid structure do not intersectwith each other.
 3. The Butler Matrix as claimed in claim 2, furthercomprising: a first coupler set, having at least four of the couplers;and a second coupler set, having at least four of the couplers, whereinfirst surfaces of the respective couplers in the first coupler set forman input array, and each side of the input array has the same number ofinput ends, second surfaces of the respective couplers in the secondcoupler set form an output array, and each side of the output array hasthe same number of output ends, and at least one of said input ends ofat least one of the couplers in the first coupler set is coupled to therespective output ends of the respective couplers of the second couplerset.
 4. The Butler Matrix as claimed in claim 3, wherein: a j^(th)output end of an i^(th) coupler in the first coupler set is coupled toan i^(th) input end of a j^(th) coupler of the second coupler set, and iand j are positive integers, j is less than or equal to 4, i is lessthan or equal to N, and N is a positive integer that is a power of 4 ormore.
 5. The Butler Matrix as claimed in claim 4, wherein: one of acombination of a first phase shifter and a second phase shifter, acombination of at least one of the plurality of crossover lines and thesecond phase shifter, a combination of the first phase shifter and atleast one of the plurality of crossover lines, and at least one of theplurality of three-dimensional crossover lines is coupled between thej^(th) output end of the i^(th) coupler in the first coupler set and thei^(th) input end of the j^(th) coupler in the second coupler set.
 6. TheButler Matrix as claimed in claim 4, wherein a first phase shifter iscoupled to a first output end and a third output end of a first couplerand a third coupler in the first coupler set, and the first phaseshifter is coupled to a second output end and a fourth output end of asecond coupler and a fourth coupler in the first coupler set.
 7. TheButler Matrix as claimed in claim 6, wherein a second phase shifter iscoupled to a first input end and a second input end of a first couplerand a second coupler in the second coupler set, and the second phaseshifter is coupled to a third input end and a fourth input end of athird coupler and a fourth coupler in the second coupler set.
 8. TheButler Matrix as claimed in claim 7, wherein the first phase shifter isconfigured to control a horizontal direction of a beamformed signal, andthe second phase shifter is configured to control a vertical directionof the beamformed signal.
 9. The Butler Matrix as claimed in claim 8,wherein the first phase shifter and the second phase shifterrespectively have a phase difference of +45 degrees, −45 degrees or −135degrees.
 10. The Butler Matrix as claimed in claim 2, wherein an m^(th)input end of one of the plurality of couplers and an m^(th) output endof the one of the plurality of couplers form a side of the cuboidstructure, and m is a positive integer less than or equal to
 4. 11. TheButler Matrix as claimed in claim 10, wherein a phase difference isprovided between an input end and an output end on a diagonal of thesame surface of the cuboid structure.
 12. The Butler Matrix as claimedin claim 11, wherein the first input end, the second input end, thefirst output end, and the second output end of the one of the pluralityof couplers form a third surface, the third input end, the fourth inputend, the third output end, and the fourth output end of the one of theplurality of couplers form a fifth surface, and the phase differencebetween one of the input ends and one of the output ends on the diagonalof the third surface and the fifth surface correspondingly is inrelation to control on a horizontal direction of a beamformed signal.13. The Butler Matrix as claimed in claim 11, wherein the first inputend, the third input end, the first output end, and the third output endof the one of the plurality of couplers form a fourth surface, thesecond input end, the fourth input end, the second output end, and thefourth output end of the one of the plurality of couplers form a sixthsurface, and the phase difference between one of the input ends and oneof the output ends on the diagonal of the fourth surface and the sixthsurface correspondingly is in relation to control on a verticaldirection of a beamformed signal.
 14. The Butler Matrix as claimed inclaim 11, wherein the phase difference is 90 degrees.
 15. The ButlerMatrix as claimed in claim 4, wherein: a k^(th) input end and a k^(th)output end in one of the three-dimensional crossover lines areelectrically connected with each other and are respectively coupled to a(5−k)^(th) output end of a k^(th) coupler in the first coupler set and ak^(th) input end of a (5−k)^(th) coupler in the second coupler set, andk is a positive integer less than or equal to
 4. 16. The Butler Matrixas claimed in claim 4, wherein the output array is a four-by-four array,and a first input end and a first output end in one of thethree-dimensional crossover lines are electrically connected with eachother and are respectively coupled to a fourth output end of a firstcoupler in the second coupler set and an output end on a third columnand a third row of the output array, a second input end and a secondoutput end in the one of the three-dimensional crossover lines areelectrically connected with each other and are respectively coupled to athird output end of a second coupler in the second coupler set and anoutput end on a second column and the third row of the output array, athird input end and a third output end in the one of thethree-dimensional crossover lines are electrically connected with eachother and are respectively coupled to a second output end of a thirdcoupler in the second coupler set and an output end on the third columnand a second row of the output array, and a fourth input end and afourth output end in the one of the three-dimensional crossover linesare electrically connected with each other and are respectively coupledto a first output end of a fourth coupler in the second coupler set andan output end on the second column and the third row of the outputarray.
 17. The Butler Matrix as claimed in claim 2, wherein said inputends of the couplers are insulated from each other, and said output endsof the couplers are insulated from each other.